Underfeed stoker-furnace



J. H. ROACH AND G. MILLER.

UNDERFEEWSTOKER FURNACE.

APPLICATION FILED APR. 16. 1918.

Patented Oct. 12,1920.

3 SHEETSSHEET I.

3mm q, Joseph H. Reach Gottlieb Miller J. H. ROACH AND G. MILLER.

UNDERFEED STOKER FURNACE.

APPLICATION FILED APR. 16, 1918.

0 2". 92 n m mm s m n m P M .a :1 M W Hm Hv win m 0 JG J. H. ROACH AND G;.MILLEB. UNDERFE'ED STOKER FURNACE.

APPLICATION FILED APR. 16, I918.

Patented Oct. 12, 1920.

3 SHEETS-SHEET 3.

5] Joseph HRoach Gottlieb Miller.

Gum/W 4 UNITED-STATES PATENT O FFICE.

JOSEPH H. RQACH, OF PHILADELPHIA, AND GOTTLIEB MILLER, 01 NORRISTOWN, PENNSYLVANIA; SAID MILLER ASSIGNOR '10 SAID R,OAGH.

UNDER-FEED STICKER-FURNACE.

- Application filed April 16,

To all whom-it may concern:

Be it known that we, JOSEPH H. ROACH, a citizen of the United States, residing at Philadelphia, Philadelphia county, and State of Pennsylvania, and GOTTLIEB MILLER, a Citizen of the United States, residing at Norristown, Montgomery county, and State of Pennsylvania, have invented anddiscovered certain new and useful Improvements in Underfeed Stoker-Furnaces, of which the following is a specification.

Our said invention-consists in various improvements in the constructionand arrangements of parts. of underfeed-stokers, whereby a more perfect feed is accomplished and the air .regulated in zones to meet the requirements I of combustion, and higher efiiciency attained, all as will hereinafter be more fully described and claimed.

Referring to the accompanying drawings,

. which are made a part hereof, and on which similar reference characters indicate similar Figure ,1 is a longitudinal section through a furnace showing a stoking apparatus of our improved construction,

Fig. 2 a cross section through the same on line22 of Fig. 1,

Fig. 3 a detail view partly in section and partly in elevation of the left'hand end of the structure shown in Fig. 1, and

Fig. 4 is a vertical transverse sectional view taken on line 4-4 of Figs. 1 and 3.

Fig. 5 is an inverted plan view as indicated by arrow 5 as shown at Figs. 1 and 3.

In said drawings, the portions marked A represent the walls of the furnace, B the supports for the grate bars and C the partitions dividing the space beneath the grate bars and retort into separate chambers.

In the main the furnace structure shown is not widely different from. other furnace structures of a more or less common type, and the description will therefore be confined chieflyto the details which constitute our improvements and the invention in the case.

The furnace is built with side ash pits 10, and a central air duct 11 extending under the retort, as is usual. The vertical partitions C divide the space beneath the grate Specification of Letters Patent. Patented Oct, 12, 1920.

1918. Serial No. 228,948.

bars and retort. into" side air chambers and a central air chamber, the side airchambers being beneath the main portion of the grate bars and dump plates 50' and thecentral air chamber beneath the retort and the head ends-of said grate bars. Blast gates 12 are provided in the partitions C for regulating the blast of air from the main air duct 11 through theside air chambers, as shown.

The retort comprises sides 13, spaced an appropriate distance apart and held by distance ferrules 14 on cross tie-rods, or bolts 51, in a well known manner. Said retort has a sliding bottom 15, the outer end of which has a shank 30 formed with a series of apertures 31 which project between ears 32 on a depending arm 33 of the ram 34 and 1s connected thereto by a pivot 35 extending through one of the perforations in said shank and perforations in said ears. The ram 34 is connected to the piston rod 16 of the power cylinder 37 by which movement is imparted to the parts. Links 38 and 39 are also connected-to a journal 52 on the depending arm 33 and in turn connected with the levers 40 and 41- pivoted at points 53 and 54 and having links 55 and 56 pivoted at their outer ends which connectsupports B, and part of=them are mounted to move and part of them are stationary. In Fig. 2 the grate-bar on the right of the figure is a stationary grate-bar, and the grate-bar on the left of the figure a movable or reciprocating grate-bar. Said movable grate-bars are operated in a usual manner by having their front lower edges recessed, and with said recesses engaging ribs on the upper side of rock shafts 21, connected to the reciprocating parts, as above described and as shown. The stationary grate-bars are formed without recesses, but have, curved faces resting upon the. ribs of the rock shafts, the faces being in the 'arc of a circle so that said rock shafts may operate freely without affecting said grate-bars at all. Each of said grate-bars is formed with twyer openings to receive the blast of air from the air chambers beneath. Said gratebars may be arranged with the stationary bars and the movable bars in alternate relation, or in any other arrangement pre\- ferred. The alternatev arrangement, will, of'

course, suggest itself as in the main appropriate,'but we do not wish to limit our invention to any specific arrangement, as the purpose of the invention can be accomplished by arranging them in any relative squeeze the coal between the opposing gratebars and force the fine coal into the twyers, greatly restricting their openings and interfering with the passage of the air. For this reason, it has been necessary in such constructions to make the twyer openings very 'narrow to avoid carrying a large amount of the fine coal and siftings into the lower passages beneath the stoker. With the construction as shown herein, wherein the twyer blocks are made stationary and the coal moved over the grate-bars. by the movement of art of said grate-bars only, the coal is fec past these twyerblocks and is distributed by the moving bars which operate with their head ends under the overhanging, or projecting, tops of the twyer blocks. This enables a definite motion to be given to the coal distribution from a retort of fixed width at the top as well as in its main part and makes it possible to have large air openings in the retort, thereby coking and thoroughly distilling the gases from the incoming fuel. i

The twyer blocks are fastened to the retort sides in any suitable manner, screw bolts 23 being shown as extending through flanges at the top of the retort sides into the lower edge of the twyer blocks. By this means the twyer blocks are easily removed and replaced whenever necessary for any cause. The grate-bar is supported at its head end by the mainstoker frame instead of being supported by the top of the retort, as in the common construction of stoking apparatus.

A further advantage of this construction is that the air distribution can be regulated to meet the conditions of fire and nearly the entire air blast can be directed into the retort and in a proper proportion under the grates without the use of partitioned gratebars. It will be noted that the head end of the grate-bar is so constructed as to exclude air from the second or grate zone except by permitting its passage through the valves or blast-gates in the main frame as shown. Separate air zones are thus maintained, one from under the retort, between its sides and the head ends of the grate-bars and the others under the grate-bars through the blast-gates.

Having thus fully described .our said invention, what we claim as new, and desire to secure by Letters Patent, is:

1. An underfeed furnace comprising a supporting structure, grate bars mounted on said supporting structure, some adapted to reciprocate while others remain stationary, contacting ribs formed upon the stationary and reciprocatable bars, and a partition dividing the supporting structure into a plurality of air conduits and having a rocking section engaging the bars at the contacting ribs adapted to actuate the reciprocatable bars and to slide in air retarding relation to the stationary bars.

2. An underfeed furnace comprising a supporting structure, grate bars mounted on said supporting structure, some adapted to reciprocate'while others remain stationary, contacting ribs formed upon the stationary and reciprocatable bars, a partition dividing the supporting structure into a plurality of air conduits and having a rocking section engaging the bars at the contacting ribs adapted to actuate the reciprocatable bars and to'slide in air retarding relation to the stationary bars, and means to drive said rocking section.

3. An underfeed furnace comprising a supporting structure, grate bars mounted on said supporting structure, some adapted to reciprocate while others remain stationary, contacting ribs formed upon the stationary and reciprocatable bars, a partition dividing the supporting structure into a plurality of aircconduits and having a rocking section engaging the bars at the contacting ribs adapted to actuate the reciprocatable bars and to slide in air retarding relation to the stationary bars, meansto drive said rocking section, and means to vary the arc of movement of the rocking section relative to the movement of the driving parts.

4. An underfeed furnace comprising a supporting structure, grate bars mounted on said supporting structure, some adapted to reciprocate while others remain stationary, contacting ribs formed upon the stationary and reciprocatable bars, a partition dividing the supporting structure into a plurality of air conduits and having a rocking section engaging the bars at the contacting ribs adapted to actuate the reciprocatable bars and to slide in air retarding relation to the stationary bars, means to drive said rocking section, and means to rock the section twice to each cycle of movement of the driving parts.

In Witness whereof we have hereunto set our hands and seals at Philadelphia, Pennlsylvania, this 5th dayof April, A. D., nineteen hundred and eighteen.

JOSEPH H. ROACH. GOTTLIEB MIL WVitnesses:

NELSON L. WEST, 7 LILLIAN A. DART.

LER. L1 8.] 

